234 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
The inheritance of the color-characters can not be dealt with so confidently, for 
the reason that wnbanded young range from typical apex to undoubted phza with all 
gradations between these extremes. The illustrations already specified show the 
typical forms. The bands of cestata individuals appear plainly at a very early age, 
but the differentiation of unbanded young into apex and phea occurs much later 
Tas_eE 178.—Partula otaheitana sinistrorsa. Tenaire Valley. Fecundity. 
No. of | Per cent | No. of | No. of Total Average | Average 
gravid.}| gravid. | eggs. | young. | contents. | for gravid. | for all. 
apex, sinistral 
cestata, sinistral 
phea. sinistral 
All, sinistral 
apex, dextral 
cestata, dextral 
phea, dextral 
All, dextral 
TasBLe 179.—Partula otaheitana sinistrorsa. Tenaire Valley. 
Fut. Statistics or HEREDITY. 
Young, sinistral. | Young, dextral. 
Plain. | Banded.} Plain. | Banded. 
Adults: 
apex, sinistral 
cestata, sinistral 
phea, sinistral 
apex, dextral 
cestata, dextral 
phea, dextral 
Summary. Herepiry oF Cott. SumMARY. HEREDITY OF COLOR-PATTERN. 
Young, | Young, Total Young, | Young, 
sinistral.| dextral. plain. cestata. Total. 
Adults: 
Sinistral.... 264 
Dextraleerercr 10 
ghotaleacer 274 
in the majority of instances. If we combine apex and cestata so as to have “plain”’ and 
“banded” divisions in parental and offspring generations, then the figures indicate 
(x) that heredity of color-pattern is regular, and possibly proceeds according to 
Mendelian principles, provided that the banded character appears a little later in 
some individuals, or (2) that the smaller relative numbers of cestata among the em- 
bryonic snails indicates a colonial change. In my opinion, the former alternative is 
preferable, especially in view of the facts observed in Titaviri. 
